Stove for blast-furnaces.



H. P. HOWLAND.

STOVE FOR BLAST FURNACES.

APPLICATION FILED APR. 30. 1915.

1,224,928. Patented May 8, 191?.

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H. P. HOWLAND.

STOVE FOR BLAST FURNACES. APPLICATION FILED APR. 30. 1915.

Patented May 8,1917.

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HENRY P. HOEVLAND, OF CHICAGO, ILLINOIS.

STOVE FOR BLAST-FURNACES.

masses;

- Specification of Letters Patent.

Application filed. April 30, 1915. Serial No. 25,076.

To all whom it may concern.

Be it known that I, HENRY P. HowLANn, a citizen of the United States, residing at Chicago, in the county of Cook and State of lllinois, have invented certain new and useful Improvements in Stoves for Blast-Furnaces, of which the following is a full, clear, and exact specification.

This invention relates to stoves for blast furnaces.

As is well-known, the primary function of a blast furnace stove is to absorb the heat liberated by thecombustion of blast furnace gas and give back this absorbed heat to air to be blown into the blast furnace. Many types of stoves of this nature have been made and used. No stove thus far produced has proved to be efficient in any marked degree. Among other things, the efficiency of a blast furnace stove dependsupon the available heating surface consistent with the proper size of gas passageway; or, in other words, proper design and location of suitablecheckers to be used in the stove.

Therefore, the main object of my invention is to improve the efficiency of blast furnace stoves.

Another object is to cause a thorough mixing of the gas and air in the stove to realize the full calorific value of the fuel.

A further object is to improve the design of checkers and properly locate the same in a stove to meet the requirements for successful commercial operation.

These and other objects are accomplished by providing the combustion chamber of a blast furnace stove with checkerwork to in crease the area of heating surface at the hottest part of the stove, said checkerwork being constructed to permit the hot products of combustion, mixture of gas and air, or cold blast, to pass from one flue to another therein for the various purposes considered.

The invention is illustrated on the accompanying sheets of drawings, in which- Figure 1 is a vertical sectional View through a'blast furn'ace stove, the sections being taken to show the hot blast outlet and the gas burner; v

Fig. 2 is another vertical sectional view of the same stove taken at right angles to the one shown in Fig. 1 and showing the chimney and cold blast inlet;

Fig. 3 is a plan view of my improved checkerwork Fig. 4 is a sectional view of the same checkerwork taken in the plane of line .i:-il: of Fig. 3;

Fig. 5 is a cross sectional view of the same checker-work taken in the plane of line 55 of Fig. 3;

Figs. (3 and 7 are sectional views of the same checker-work takenin the planes of lines 66 and 77, respectively, of i; and

Figs. 8, 9 and 10 are sectional views in the planes of lines 8-8, 9--9 and 10-10, respectively, of the bottom checkerwork shown in Figs. 1 and 2.

The various novel features of my invention will. be apparent from the following description and drawings, and will be particularly pointed out in the appended claims.

The efficiency of a blast furnace stove has been a big problem ever since stoves for "such purposes have been used. Various types of these stoves which have been thoroughly tried out in practice, have proven to be cfiicient to a very small degree. The primary function of the blast furnace stove being to absorb the greatest amount of heat liberated by the combustion of blast furnace gases and to heat the cold blast of air later to be passed therethrough and into the blast furnace, it is of paramount importance that the maxi mum heating surface should be presented consistent with the size of openings through which the gas passes. Generally speaking, the smaller the checker or passageway, the greater will be the heating surface in the stove. This is because of the greater number of small checkers that can be placed in a given area. But, on the other hand, the checkers or openings must be large enough so that they will not become stopped with dirt and thereby become useless. Again, generally speaking, the smaller the checker, the greater the likclihood there is of the checkers becoming stopped up with dirt.

These two propositions are diametrically opposed, and the result has been a medium between the two extremes. The problem of getting a large amount of heating surface can be solved in two ways: First, by the use of large checkers, which means a very large stove, leading to many complications in correct design and costing much'to erect. In order to get sufiicient heating surface by this method it has sometimes been advisable to build as many as live stoves for a single blast furnace. Second, by removing the dirt from the gas, which thus permits of the use of small checkers, and Consequently a large heating surface in small stoves. As is wellknown, this gas cleaning is generally done by spraying the gas with water, the process being known as gas washing. Clean gas has many advantages, and is now coming into general use throughout this country. As a rule, however, very few stoves have been built which were designed exclusively for the use of clean gas, and stoves already erected for burning dirty gas have not been changed to be particularly adapted to burn clean gas and obtain the highest efficiency of the stove; in other words, stores designed for the use of dirty gas are now using clean gas. This means that checkers now in use are much larger and the heating surface much smaller than could be used in a stove had the latter been built for washed gas. It is a very expensive operation to tear down this old checkerwm'k and build it up anew with smaller checkers. 'Jlhereforc, l have solved this problem by doing two things. First, I provide the combustion chan'iber 15 of the blast furnace store 16 with checkers 17, 18, 19, 20, 21 and Second, by designing these checkers in a manner to render them highly eilicient, especially when. used in the combustion chamber.

The gas enters the stove through the gas burner 23 eithe' already mixed with air or is mixed with air within the stove, the air in the latter case also entering at the bottom of the stove. This gas is burned in the combustion chamber 15 and as hot products of combustion is delivered therefrom through the dome 24-v to the usual checkers 25, where more or less heat is absorbed from the burning gas. By placing checkers in the combustion chamber the efficiency of the stove is greatly increased for two reasons: First, the heating surface of the whole stove is illcreased by a comparatively great amount. Second, this increased heating surface is in the hottest part of the stove, and, therefore, becomes much hotter than any other of the checkerwork. The gas is delivered from the checkers in the combustion chamber to the other checkers 25 much cooler than heretofore has been the case, and consequently, after being further cooled by these checkers 25, the goes to the chimney 2G much cooler than under the old practice.

By placing a. large number of checkers in a combustion chamber it might be said that practically no combustionchamber remains, which might, under some conditions, result in incomplete mixing and incomplete combustion of the gas. However, with the particular design of the checkers; such, for example, as 18, 19, 20 and 21, the gas and air are completely mixed and consumed. If gas and air are poorly mixed, it might be possible, with a straight flue checker, for one checker to have a mixture passing up through it with an excess amount of gas and a checker next to it with an excess amount of air. This would be a serious objection to putting these checkers in the combustion chamber. However, my specially designed checkerx'vork.compels the air and gas to become thoroughly mixed and consumed as they pass up through them. It will be noted that the checkerwork includes any number of suitable layers, such as 27, 28, 29, 30, 31, 32, 33, 3 1- and of suitable lire brick.

Referring to Fig. 6, it will be noted that the second layer 28 has a plurality of transversely extending rows of brick 36, the brick being spaced in a manner to form transversely extending openings 37 between adjacent main passageways 38, 39, 40, etc, the gas and air passing through said transverse openings 37 into the main passageways 38, 39 and 40, causing a thorough mixing of the air and gas. If the air and gas are already thoroughly mixed, the burning gas or hot products of combustion also may come into intimate contact with the walls of the passageways and openings, thereby imparting an increased amount of heat thereto. The air and gas would not be thoroughly mixed or the hot products of combustion, and also the cold blast of air impinge on a greater amount of absorbing and radiating surface, if it were not for the fact that these main passageways or checkers 38, 39 and 4L0 were interconnected by the openings therebetween. Thus the importance of these main passageways or checkers being connected by communicating openings 37. Reference being had to Fig. 7, it will be noted that layer 31 of fire brick is exposed. Here another plurality of series of brick tl, running in a different direction, are shown, the brick being spaced apart to form openings 42 connecting any number of the same main passageways, such as 38, 39 and 10, with other lateral main passageways l3, 44 and 45 arranged adjacent the first series of openings 38, 39 and 40. In this way gas and air, or hot products of combustion, or a blastvof cold air, may not only pass transversely from one main passageway to another in one direction, but also from one main passageway to another in a different direction, and, indeed, take a spiral path through checkerwork for accomplishing the desired results. In this way the gas may be completely consumed to liberate the maximum amount of heat to be absorbed by the increased exposed surface of brick forming the checkerwork. On the other hand, a cold blast passing through this checkerwork will become heated to a higher degree before passing into the blast furnace.

By means of this type of checkerwork having the connecting openings, the heating surface is greatly increased, and at the same time the amount of brick necessary to construct these checkers in this manner-is proportionately decreased. It is to be remembered also that gas passing through adjacent checkers in stoves used heretofore undoubtedly differed in temperature. This means undoubtedly different velocities and pressures in these various checkers. Such condition is probably due to the fact that it is almost impossible to deliver the same amount of gas to individual checkers, and even though it were distributed equally, the draft would not act equally on all of the checkers. By means of the construction of checkerwork I have provided, the gas or products of combustion, and also the cold air blast, are allowed free passage from one main passageway or checker to another, thereby providing means for the elimination of irregularities hereinabove set forth and for the cold blast absorbing the maximum amount of heat. In connection with the question of heat absorption, undoubtedly the best heat absorption can be accomplished when each particle "of gas is brought into contact with as much heating surface as possible. In the flue type of checkerwork it would be perfectly possible for the gas to pass through the checker and for the layers of gas next to, the brick to form an insulating film which would prevent the gas in the middle of the checker from giving up its heat to the walls. by skin insulation. The only way to over come this skin insulation is to break up the thin film of gas adjacent the brick. This will result in changing the flow of all the gas in the checker. The opening lead- .ing from one main passageway to another in the checkerwork will do this very nicely. Also the same effect may be increased, if desired, by placing any desired number of brick 48 so that they will project into the checkers or main passageways, such as 38, 39, 4L0, 43, 44, 45, etc. In this Way the skin insulation will be completely eliminated. By means of these methods the flow of fluid in both directions in the checker will be distributed to accomplish the desired results.

The checkerwork as a whole in the combustion chamber 15 includes vertically extending wall sections between each two of the other checker members 17 to 22, inclusive, the whole checkerwork being supported by suitable arch work 56. The wall sections 55 form checkers or passageways 57 registering with the checkers in the checkerwork 17 to 22, inclusive. The checkerwork members 17 to 22, inclusive, are spaced in and located at points along the length of the combustion chamber.

As is well-known, the gas or products of combustion for heating the stove passes in through the gas burner 23, the gas being burned in the combustion chamber 15, where This is what is meant its heat is liberated to permit its absorption by the checkerwork in the combustion chamber, the gas continuing upwardly into the dome 2%, from which it passes downwardly through the usual checkers 25, from which the gas passes, in a relatively cool condition, out through the chimney 26. This heating process of the checkerwork continues for about three hours, whereupon the cold air is blown through the cold blast passageway 50 up through the usual checkers 25, through the dome 2-l and downwardly through the checkerwork in the combustion chamber, and out through the hot blast passageway 51 to be conveyed to the blast furnace. It will be noted that by means of this arrangement the greatest amount of heat from the burned gas is given to the checker- Work in the combustion chamber, and the remainder of the heat given to the other checkers 25 as the gas passes downwardly therethrough and out of the chimney 26. It will be noted further that the cold blast is first led into the lower ends of the checkerwork 25, where it becomes warmed by absorbing heat from the walls thereof, and then passes through the dome 24: and clownwardly through the checkers in the combustion chamber to receive its greatest amount of heat just prior to passing out of the stove and into the blast furnace.

This arrangement of checkers in the combustion chamber, and with the particular design of checkerwork, has proven commercially to increase the efficiency of stoves by a very great amount. It is evident that there may be various modifications of the precise form and arrangement herein shown and described, and it is my intention to cover all such modifications which do not involve a departure from the spirit and scope of my invention as set forth in the following claims.

What I claim as new is:

1. In a blast furnace stove, a single central combustion chamber formed therein, and checkerwork members having connected passageways located in and at points along the length of the combustion chamber.

2. In a blast furnace stove, a combustion chamber formed therein, vertically arranged checkerwork members Within said combustion chamber, and checkerwork members within the combustion chamber extending crosswise at points along the length thereof.

3. In a blast furnace stove, a centrally arranged combustion chamber formed therein, and means including a checkerwork member having passageways with connections therebetween, through which connections air and gas pass to be thoroughly mixed.

4. In a blast furnace stove, a central combustion chamber formed therein having a plurality of passageways for the passage back and forth of hot products of combustion and a cold air blast, and means for interconnecting said passageways within the combustion chamber to increase the heat absorbing and radiating surface therein.

5. In a blast furnace stove, a central combustion chamber formed therein, and means including members with interconnected passageways in said combustion chamber to cause a mixed fluid fed thereto to take an irregular path in passing therethrough.

6. In a blast furnace stove, a central combustion chamber formed therein, and checkerwork mounted in said combustion chamher having a plurality of walled passageways, the walls of said passageways being provided with openings to permit a mixed fluid passing through one of said passageways to flow through said openings into another of said passageways.

7 In a blast furnace stove, a central combustion chamber formed therein, and checkerwork mounted in said combustion chamber having a plurality of walled passageways, the walls of said passageways being provided with openings in a plurality of directions to permit heat liberating and heat absorbing fluids passing through one of said passageways to flow through said openings into other of said passageways and back again.

8. In checkerwork for blast furnace stoves, the combination of intersecting walls forming a plurality of passageways, said walls having obstructing projections and also openings therein for connecting saidpassageways.

9. In checkerwork for blast furnace stoves, the combination of intersecting walls forming a plurality of passageways, said walls having obstructing projections and also openings therein in different directions to connect the main passageways lying adjacent in different directions.

10. In checkerwork for blast furnace stoves, the combination of intersecting walls ways to cause an interrupted movement of a fluid passing therethrough.

12. In checkerwork for blast furnace stoves, the combination of intersecting walls forming a plurality of passageways, said walls having openings therein to permit the passage of a fluid from one of said passageways to other passageways lying in different directions, and means projecting from one of said walls into one of said passageways to cause an interrupted movement of fluid passing therethi'ough.

13. In checkerwork for blast furnace stoves, the combination of intersecting walls forming a plurality of adjacent passageways, said walls having openings in different directions to permit the passage of a' fluld from one passageway to others 1n d1fferent directions, and members projecting from certain of said walls into one of said passageways to cause interrupted movement of fluid passing'therethrough.

14. In a blast furnace stove, a combustion chamber formed therein, and alternately arranged vertically extending and crosswise extending checkerwork members within said combustion chamber.

In testimony whereof I affix my signature in the presence of two witnesses.

HENRY P. HOWLAND.

Vitnesses:

W. C. HANSEN, J. A. READ.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0." 

